Apparatus and method of painting



June 13, 1961 H. A. BUELOW ETAL 2,988,459

APPARATUS AND METHOD OF PAINTING Filed on. 27, 1958 2 Sheets-Sheet 1 June 13, 1961 H. A. BUELOW ETAL 2,983,459

APPARATUS AND METHOD OF PAINTING Filed Oct. 27, 1958 2 Sheets-Sheet 2 IN VENTORS F Mi United States Patent Filed Oct. 27, 1958, Ser. No. 769,839 4 Claims. (Cl. 117-102) The invention relates to a method of, painting and the apparatus utilized therewith.

The invention has particular reference to a method of removing excess paint from an end product and supplementing gravity drainage of such excess paint.

One object of the invention is to provide apparatus for creating an evenly distributed flow of pressurized air.

Another object is to provide apparatus employing pressurized air supplemented by aspirated air for achieving, greater uniformity of air flow.

The invention has particular utility in connection with the painting of an end product where the basic application of the paint involves the principle of applying an excess quantity of liquid paint to the end product and then utilizing gravity for draining such excess paint from the end product. Such painting methods include the methodof dip painting, where the end product is dipped into a stored quantity ofliquid paint and then withdrawn therefrom and the method identified as flow coating, where the end productis introduced into an area where liquid paint is flowed under very low pressure thereonto and the; excessive paint is drained by gravity from such end product.

In these types of painting methods, if the end product has certain. areas from which the excess paint cannot be readily drained by gravity, then it is necessary to either tilt the end product so that such drainage can be accomplished or employ some supplementary method of removing such excess paint. In the instant application, it is not feasible to tilt the end product for paint drainage purposes and consequently the inventive subject matter is employed for accomplishing the necessary drainage. In effecting such drainage, it is necessary to control the uniformity of the ultimate coating ofpaint-particularly with reference to accomplishing uniform thickness of such coating.

Other objects and advantages of the invention will be apparent from the specification and appended drawings in which:

FIG. 1 is a side elevational view of a paint dip tank showing an end product, in this instance an automobile body, being lowered into the tank while suspended from an overhead rail.

FIG. 2 is a perspective view of a portion of the end product shown in FIG. 1 and illustrating the method and apparatus for removing excess paint from such end product.

FIG. 3 is a plan view similar to FIG. 2 but on a considerably reduced scale.

FIG. 4 is a side view similar to FIG. 2 but on a considerably reduced scale.

FIG. 5 is a perspective view, partly in section, of the apparatus utilized in the method.

FIG. 6 is a sectional view taken on the irregular line 66 of FIG. 5.

FIG. 7 is a fragmentary sectional view taken on the line 77 of "FIG. 4.

In general the apparatus involved in the method of removing excess paint includes a closed housing member A having an elongated air discharge opening B at one end thereof. Air pressure is introduced into the upper end of the housing through appropriate air conduction means C and the housing is provided with vent openings D for admitting aspirated air.

The housing may be formed of spaced panels 10 and 11 with appropriate end wall panels 12 and 13. A manifold in the form of a length of tubing 14 closed at each end is secured at the upper end of the housing, extending throughout the length thereof, and serves to close oif the otherwise open upper end of the housing. A primary air inlet conduit 15 opens into the manifold conduit 14 and is rigidly secured thereto. A series of discharge jets 16 are spaced equidistantly along the length of the manifold conduit 14 and such jets open into the manifold conduit 14. Air is introduced under high pressure (from anysuitable source of compressed air, not shown) into the manifold conduit 14 through the primary air inlet conduit 15 and is discharged out through the several jets under high velocity. In practice I have found that air pressure in the neighborhood of 25 p.s.i. at the inlet conduit 15 is adequate for achieving the desired velocity at the housing discharge opening B, however, it will be understood that variations in the amount of air pressure above or below 25 p.s.i. may exist without materially affecting the end results obtained with the blowing device. The jets 16 may be in the form of suitable lengths of standard tubing, such as A, however, it will be understood that the ID. of such jets may vary from between A3" to A.

Each of the housing panels 10 and 11 is appropriately slitted so that the portions 18 and 19 can be struck outwardly forming the baflles which assist in directing additional air into the interior, of the housing through the elongated panel openings 20 and 21such additional air being aspirated into the interior of the housing under the influence of the high velocity air being discharged at the outlet ends 16a of the jets 16. By adding the aspirated air into the interior of the housing, the individual streams of air being discharged from the jets are substantially converted into a generally uniformly distributed flow of high pressure air at the elongated discharge opening B at the lower end of the housing. The uniformity of, the air flow at the discharge opening B of the housing assures a resultant coating of paint of uniform thickness as desired.

In the drawings, the width of the discharge opening B in proportion to the actual size of the housing A is somewhat exaggerated for disclosure clarity purposes and in practice, it is usually desirable to confine the width of the discharge opening to about 1 thereby assuring the desired air velocity in proportion to the pressure of the incoming air entering the inlet conduit 15.

The method FIG. 1 illustrates the dip painting of an end product which, as shown, is an automobile body and it will be understood that the same apparatus of FIG. 1 could be used in a flow coating painting method wherein liquid paint from several discharge nozzles would be flowed onto the automobile body as it moves along the conveyor rail 30. After the end product 31 leaves the dip tank 32, the excess paint thereon drains therefrom by gravity. Certain areas on the end product may be situated so that gravity drainage is not possible, such an area being indicated by the numeral 33 in FIG. 2. This area is somewhat recessed and in a dip or flow coat type of painting, excess paint would accumulate in this recessed area 33. Consequently, immediately after the end prod not is withdrawn from the dip tank 32 it is desirable to remove the excess paint accumulation in the area 33. This is done by introducing the air blowing device immediately above the surface of the area 33. The lower edge of the blower device is preferably formed (as shown best in FIG. 5) so as to conform generally to the crosssectional configuration of the recessed area 383. Thus, the lower edge of the blower device can be supported manually by an operator within a fraction of an inch (as best shown in Fig. 7) above the surface of the end product while it is being advanced along the length thereof. The device is preferably tilted from the vertical at an angle approximately as shown in Fig. 4 and the device is likewise tilted angularly with reference to the longitudinal line of the recessed area 33 at an angle approximately as shown in Fig. 3. The latter tilting of the device will cause the excess paint to be blown so as to spill over the longitudinal edge 34. As the device is moved manually along the longitudinal extent of the recessed area 33, the uniformly discharged flow of air from the elongated opening B causes the excess paint 4 V l maintaining the blower device in the previously established positioning with reference to the surface, whereby the air pressure causes the excess paint to flow over one longitudinal edge of the surface.

2. A blower device for discharging an elongated sheet of high velocity air having substantially uniform volume and velocity throughout the length of the sheet; said device comprising: a housing having spaced end Walls and spaced side walls converging and terminating to define an elongated narrow discharge opening, said side walls being several times greater in width than the end walls; air inlet conduit means secured to the housing remote from the discharge openin'g;a tubular manifold to be flowed out of the recessed area and spilled over the edge 34 and the resultant coating in the area 33 is of substantially uniform thickness as desired.

While we have indicated certain dimensions for the jets 16 and the discharge opening B and while we have indicated a desired air pressure at the inlet 15, it will be understood that these factors may be varied in accordance with the size and capacity of the blowing device and we do not wish to be limited to the dimensions and pressure recited herein.

We claim:

1. A method of removing a portion of the liquid paint from a freshly painted end product having a generally horizontally disposed upper surface with spaced longitudinal side edges such that liquid paint applied thereto in an excessive quantity will not adequately drain over either side edge therefrom by gravity, such method including the steps of: manually grasping a portable air blower device having an elongated narrow discharge mouth for discharging a thin sheet of pressurized air therefrom; positioning the blower device above the surface with the discharge mouth disposed immediately adjacent the surface, such positioning including inclining the blower device rearwardly with reference to a vertical plane and with reference to the direction of progress to be imparted to the blower device so that the sheet of air is directed onto the painted surface in a plane inclined from the vertical and such positioning including turning the discharge mouth so that its longitudinal center line defines an acute angle with reference to the longitudinal side edges of the painted surface, whereby one end of the sheet of air trails the other end so that the excess paint is substantially all discharged over the longitudinal side edge which is nearest the trailing end of the sheet of air; then manually moving the blower device along the surface in a direction generally parallel with the longitudinal side edges of the end product while positioned between the side walls and closing oif the end of the housing remote from the discharge opening, said manifold serving to deliver air through the housing toward the discharge opening; aplurality of air discharge pipes in communication with the'interior of the manifold and arranged successively along the length of the manifold; said manifold being open to the conduit means and in conjunction with the discharge pipes serving to spread the air out into an air flow path which is several 7 times wider than the path of the air as it passes through the air inlet conduit means; said housing having an air inlet opening for admitting aspirated air into the housing where such aspirated air is mixed with the air which is passing through the housing from the manifold toward the discharge opening; and the discharge ends of the discharge pipes being directed toward the housing discharge opening and being situated relative to the housing discharge opening a dist-ance less than the distance which the air inlet opening is situated relative to the housing discharge opening. 3. A blower device as set forth in claim 2 wherein the air inlet opening which is formed in the housing wall extends throughout a major portion of the width thereof so as to be exposed to the plurality of air discharge pipes. 4. A blower device as set forth in claim 2 wherein the air inlet opening in the housing is formed by striking out a portion of the housing wall to form a bafiie projecting angularly outwardly from the housing wall.

References Cited in the file of this patent UNITED STATES PATENTS Hurst Aug. 21, 1957 

1. A METHOD OF REMOVING A PORTION OF THELIQUID PAINT FROM A FRESHLY PAINTED END PRODUCT HAVING A GENERALLY HORIZONTALLY DISPOSED UPPER SURFACE WITH SPACED LONGITUDINAL SIDE EDGES SUCH THAT LIQUID PAINT APPLIED THERETO IN AN EXCESSIVE QUANTITY WILL NOT ADEQUATELY DRAIN OVER EITHER SIDE EDGE THEREFROM BY GRAVITY, SUCH METHOD INCLUDING THE STEPS OF: MANUALLY GRASPING A PORTABLE AIR BLOWER DEVICE HAVING AN ELONGATED NARROW DISCHARGED MOUTH FOR DISCHARGING A THIN SHEET OF PRESSURIZED AIR THEREFORM, POSITIONING THE BLOWER DEVICE ABOVE THE SURFACE WITH THE DISCHARGE MOUTH DISPOSED IMMEDIATELY ADJACENT THE SURFACE, SUCH POSITIONING INCLUDING INCLINING THE BLOWER DEVICE REARWARDLY WITH REFERENCE TO A VERTICAL PLANE AND WITH REFERENCE TO THE DIRECTION OF PROGRESS TO BE IMPARTED TO THE BLOWER DEVICE SO THAT THE SHEET OF AIR IS DIRECTED ONTO THE PAINTED SURFACE IN A PLANE INCLINED FROM THE VERTICAL AND SUCH POSITIONING INCLUDING TURNING THE DISCHARGE MOUTH SO THAT ITS LONGITUDINAL CENTER LINE DEFINES AN ACUTE ANGLE WITH REFERENCE TO THE LONGITUDINAL SIDE EDGES OF THE PAINTED SURFACE, WHEREBY ONE END OF THE SHEET OF AIR TRAILS THE OTHER END SO THAT THE EXCESS PAINT IS SUBSTANTIALLY ALL DISCHARGED OVER THE LONGITUDINAL SIDE EDGE WHICH IS NEAREST THE TRAILING END OF THE SHEET OF AIR, THEN MANUALLY MOVING THE BLOWER DEVICE ALONG THE SURFACE IN A DIRECTION GENERALLY PARALLEL WITH LONGITUDINAL SIDE EDGES OF THE END PRODUCT WHILE MAINTAINING THE BLOWER DEVICE IN THE PREVIOUSLY ESTABLISHED POSITIONING WITH REFERENCE TO THE SURFACE, WHEREBY THE AIR PRESSURE CAUSES THE EXCESS PAINT TO FLOW OVER ONE LONGITUDINAL EDGE OF THE SURFACE. 